Binocular artificial vision is an extension of a photogrammetric stereo image-correlation technique that has been developed as a rapid means of extracting three-dimensional topographic information from aerial photographs (See for example U.S. Pat. No. 3,659,939). In aerial surveying the object to be defined, usually the surface of the ground as seen from considerable altitude, can usually be regarded as a single convoluted or undulated surface. The general continuity of the resultant model surface simplifies "correlative matching" since successful correlation of any small part of the model leads to a rapid spread of correlation and matching over the entire area under examination.
Such a system is shown in FIG. 1 which illustrates schematically the elements of a binocular stereo correlation system suitable for photogrammetric purposes.
Referring to FIG. 1, a pair of transparent "diapositive" aerial photographs 1 and 2 (left and right respectively) are illuminated by light sources 3 and 4 respectively and viewed by left and right video cameras 5 and 6 respectively. The cameras generate left and right video signals on lines 7 and 8 respectively which are delivered to the stereo correlator 9. Topographic height data is computed within the correlator and delivered via line 10 to external storage or display means.
The application of such photogrammetric stereo image-correlation techniques to an artificial vision system dealing with three-dimensional workspace environments is severely limited by the discontinuous nature of a workspace containing both close and distant objects separated from each other and from the background by significant distances. As the stereo images from such a scene are scanned and processed, abrupt changes in distance will occur whenever the correlator encounters an object edge. Such discontinuities prevent the spread of correlation so that some means must be found to initiate the correlative matching process within each area bounded by spatial discontinuities including the edges of the field of view.